Apparatus for a shot peening treatment

ABSTRACT

A shot-peening device(s) is installed on a side of a cabinet defining an ejection chamber in the cabinet. Shots ejected from the device to a workpiece fall and are conveyed in a horizontal direction by a horizontal screw conveyor positioned above a lower end of the cabinet and then conveyed upward by a vertical screw conveyor whose base end is above the lower end of the cabinet. The shots pass from an upper section of the vertical screw conveyor through a chute to reach an opening/closing gate. When the gate is opened and the shots are supplied to the device(s) for re-ejeciton, a portion of the shots is cause to overflow from the gate. The overflowed shots are caused to pass through a separator to remove impurities and then returned to the horizontal screw conveyor.

FIELD OF THE INVENTION

This invention relates to an apparatus for treating an object with shotparticles.

BACKGROUND OF THE INVENTION

Shot-peening devices for projecting spherical particles, namely, shotparticles, to the surface of a work piece to be treated, are known.Those devices include a nozzle-type device relevant to projecting theshot particles in relatively small volumes (e.g., Japanese PatentEarly-Publication 2002-326161, assigned to the applicant) and animpeller-type device relevant to projecting them in relatively largevolumes (e.g., Japanese Patent Early-Publication 11-239973).

An apparatus for a projection treatment equipped with a shot-penningdevice is one such as a shot-blasting machine or an air-blasting machinein which a workpiece is treated. In such an apparatus, the shot-penningdevice is mounted on a cabinet defining a projecting chamber therein.The shot-peening device projects short particles to a workpiece that issupported on a movable carriage. In such an apparatus, a circulationsystem for collecting the projected shot particles and returning them tothe shot-peening device is also known (e.g., Japanese Patent EarlyPublication 59-187462 and the above-mentioned Japanese PatentEarly-Publication 11-239973).

However, there is a problem in that the height of the apparatusdisclosed in these publications is increased because a large circulationsystem is needed to collect the projected shot particles from theshot-peening device. In particular, in the shot-blasting machine withthe impeller type shot-peening device, more particularly for the machinewith plural devices, for projecting the shot particles in large volumes,the size of the circulation system is further increased and thus themachine needs the greater height. Accordingly, a large space is neededto install the blasting machine.

Further, the conventional circulation system in the blasting-machine isdesigned such that a collecting position in which the circulation systemcollects the shot particles that fall because of their own weight islocated beneath the bottom end of a cabinet. Accordingly, a recess or apit is needed in the area where the blasting machine is to be installed.Because the pit is located beneath the level of the floor or base onwhich the machine is to be installed, time and effort is necessary toconstruct such a pit.

Similarly, because the conventional blasting-machine is designed suchthat its lower portion to be received in the pit protrudes from thebottom end of the cabinet, the machine has an unstable stand when it isremoved from the pit. Namely, such a design of the machine isinappropriate to transport and package the machine. To transport such anunstable machine, at least part of the machine should be reassembled.For example, to deliver the machine as the product to a user's factoryfrom a manufacturer's firm, the following steps are needed. The machineis first trial assembled and temporarily installed to make a trialoperation of it at the manufacturer's firm. Following the trialoperation, the machine should be reassembled in order to transport it tothe user's factory. In the factory, the delivered machine isre-assembled and installed, and this necessitates effort to constructthe pit. Alternatively, say, any relocation of the user's factory meansthat the installed blasting machine should be transported to the newlocation and re-installed. In this case, the machine should bereassembled for transportation from the original location, and should bere-assembled and installed in a new location. This takes effort toconstruct the pit in the new location. Accordingly, it takes time andeffort to both introduce a new machine and relocate it.

DISCLOSURE OF THE PRESENT INVENTION

Therefore, the object of the present invention is to provide anapparatus for a shot-peening treatment that is compact such that it canbe installed in a relatively small space without a pit for installingit, and its transport can also be readily achieved.

The apparatus for the shot-peening treatment relating to the presentinvention includes 1) a housing having upper and bottom ends anddefining the interior therein, 2) a movable carriage for movablysupporting an object to be treated within the interior, 3) at least oneprojection means for projecting shot particles to the object supportedby the carriage, and 4) a circulation system having a collecting levelin which the projected and fallen shot particles are collected to returnthe collected shot particles to the projection means in order to recycleand use them for the projection.

Thus the apparatus of the present invention is characterized in that thecollecting level is located at a level that is the same as or higherthan that of the bottom end of the housing.

The circulation system includes at least one cross feeder. It ishorizontally arranged at the collection position, for cross feeding theshot particles. It also includes at least one vertical feeder forupwardly feeding the shot particles that are cross fed by the crossfeeder.

It also includes a diversion means for communicating with the crossfeeder at the fixed position above the collecting level and has a closedposition and an open position in which an aperture of it can be varied.The diversion means in the closed potion diverts all of the incomingshot particles that arrive at the fixed position by means of thevertical feeder, while the divider means in the open position dividessome of the shots, based on the variable aperture, of the incoming shotparticles that arrive at the fixed position by the vertical feeder. Thediversion means returns the shot particles that are not diverted to theprojection means.

It also includes removing means provided between the diversion means andthe collecting level such that the shot particles that diverge from thediversion means pass through therein for eliminating impurities fromthese shot particles.

To further lower the height of the apparatus, preferably the fixedposition, in which the diversion means is provided, is located under theupper end of the housing. In such an arrangement, the removing means maybe located within the housing.

There is a plurality of each of the cross feeder, the vertical feeder,the projecting means, the diversion means, and the removing means. Insuch an arrangement, the shot particles are supplied to the respectiveprojection means from the corresponding vertical feeder via its matingdiversion means.

In the embodiments of the present invention, the cross feeder is a screwconveyor, horizontally arranged. The vertical feeder is a screwconveyor, substantially vertically arranged, or a bucket conveyor.

Decreasing the power of the vertical feeder is achieved to lower thelevel of the apparatus and thus to decrease the vertical travelingdistance of the vertical feeder. To this purpose, preferably the levelat which the removing means is located is substantially the same as orlower than that of the diversion means that communicates with thevertical feeder at the fixed position. In such an arrangement, the shotparticles diverge from the diversion means in its opening position basedon its overflow from its variable aperture from the diversion means suchthat they are readily introduced into the removing means.

In the embodiments of the present invention, the housing is providedwith one or more elongated grooves along the traveling direction of thecross feeder. Therefore, one or more cross feeders is received in thegroove at the collection level, which is located above the bottom end ofthe housing. The groove includes an inclined surface for guiding theshot particles to the cross feeder.

If plural cross feeders are provided, a plurality of the grooves may beprovided, so that each groove receives one cross feeder such that theplural cross feeders are arranged in parallel to each other.

In this case, if too many shot particles flow into one groove, thiscauses an overload of the corresponding one cross feeder in the relatedone groove. To prevent such an overload of the cross feeder, preferablysome means for spreading the shot particles to respective grooves isfurther provided.

Preferably, the projection means is attached to a sidewall of thehousing such that the former is integrally provided with the latter. Theprojection means includes an impeller type shot-peening device or anozzle type shot-peening device. The impeller type shot-peening devicesmay be arranged at the top and the bottom. The apparatus may include ashot-blasting machine, an air-blasting machine, or a shot-peeningsystem.

In one embodiment of the present invention, a dust collector is mountedon an outer sidewall of the housing to suck the interior of the housingthrough a suction tube. The suction tube is preferably connected to asource for supplying an ignition suppressant in order to restrain anyignition of the dust within the dust collector.

Preferably, a plurality of flattened cartridge filters is arranged inthe dust collector.

The carriage may use a conveyor type, a hanger type, a table type, or adrum type, carriage.

BRIEF DESCRIPTIONS OF THE FIGURES

FIG. 1 is a schematic front elevation view of a shot-blasting machine ofthe first embodiment of the present invention.

FIG. 2 is a schematic side view, partly in cross section, of the machineof FIG. 1.

FIG. 3 is a schematic front elevation view, partly in cross section, ofthe air-blasting machine of the second embodiment of the presentinvention.

FIG. 4 is a schematic side view of the shot circulation unit of themachine of FIG. 3.

FIG. 5 is a schematic rear view of the shot separator used for themachine of FIG. 3.

FIG. 6 is a schematic front elevation view of a shot-blasting machine ofthe third embodiment of the present invention.

FIG. 7 is a schematic side view of the circulation unit of the machineof FIG. 6.

FIG. 8 is a front elevation view of a shot-blasting machine of thefourth embodiment of the present invention.

FIG. 9 shows a view along the line A-A of FIG. 8.

FIG. 10 shows a view along the line B-B of FIG. 8.

FIG. 11 shows a view along the line C-C of FIG. 8.

FIG. 12 shows a view of the circulation unit along the line D-D of FIG.10.

FIG. 13 shows a view of the dust collector along the line E-E of FIG. 9.

FIG. 14 shows a view of the dust collector along the line F-F of FIG. 6.

PREFERRED EMBODIMENTS OF THE INVENTION The First Embodiment

FIGS. 1 and 2 show a shot-blasting machine as the first embodiment ofthe shot-peening treating system of the present invention. Theshot-blasting machine includes a cabinet (or housing) 1 defining aprojection chamber therein and two shot projecting means such as twoimpeller type shot peening devices 2 mounted on both sidewalls of thecabinet. Each shot-peening device 2 projects shot particles by means ofthe centrifugal force of an impeller. The shot-blasting machine alsoincludes a hanger type, movable carriage 3 arranged in a projectionchamber to suspend and transport a work piece (for example, a forge, aheat-treatment article) to be treated, and a shot circulation unit orsystem to collect the projected shot-particles and return them to theshot-peening devices 2.

In FIG. 2, the shot circulation unit denoted by R includes a pair ofcross feeders or horizontal screw conveyers 4 for feeding the projectedshot particles in a horizontal direction such that they are gatheredon 1) the corresponding locations, each located outside the cabinet 1,and 2) a pair of vertical feeders or substantially vertical screwconveyors 6 for feeding the gathered shot particles upwards. Thecirculation unit also includes two shot separators 11. Each communicateswith the respective vertical feeder such that it eliminates impuritiesfrom the shot-particles to be supplied to the respective shot-peeningdevice 2. In FIG. 1, each vertical feeder 6 is shown as its cover 7, inwhich the vertical feeder 6 is enclosed.

The cabinet 1 is designed such that the shot-blasting machine can beinstalled without a pit, although the conventional shot-blasting machineneeds such a pit for installing it in which a position for collectingthe projected and fallen shot particles protrudes below the lower end ofthe cabinet 1. To this purpose, the lower part of the cabinet 1, viewfrom the front, forms a W-shape as shown in, especially, FIG. 1. Thelower part of the cabinet includes two parallel grooves 5 that extend inthe traveling direction (the normal direction against the surface ofFIG. 1) of the cross feeders. Each groove 5 has inclined surfaces forcollecting the shot particles. The level of it corresponds to thecollecting level in which the shot particles are collected, in thisembodiment. In each groove 5, the respective cross feeder 4 of thecirculation unit is arranged. The level of the bottom of the respectivegroove 5 is located at the same level as, or above, the level of thebottom end of the cabinet 1. (In this embodiment, the level of thegroove 5 is located slightly above the bottom end of the cabinet 1.)Therefore, the bottom ends of the cross feeders 4 within the grooves 5cannot project below the bottom end of the cabinet 1. The proximal endsof the vertical feeders 6 are also located above the bottom end of thecabinet 1. In other words, once the shot blasting machine of the presentinvention is installed, the bottom end of the cabinet 1, and thus thebottom ends of the cross feeders 4 and the proximal ends of the verticalfeeders 6, will be located above the level of the floor (or a base) onwhich the shot blasting machine is to be installed. Therefore, theshot-blasting machine of the present invention needs no pit for itsinstallation, and thus the installation and transportation of it can bereadily achieved.

The inclined surfaces of the grooves 5 help to guide the projected andfallen shot particle to the cross feeders 4. The inclination of eachinclined surface of the respective groove 5 is preferably from 20 to 40degrees, in consideration of the angle of repose of the shot particle,and of the condition to readily guide the shot particles and thus toextend their life cycles. This is similar to the other embodiments.

In FIG. 2, a rotor M is drivingly connected to one side of the upperportion of the respective vertical feeder or vertical screw feeder 6.The other side of the upper portion of the respective vertical feeder 6communicates with a chute 8. The lower end of the respective chute 8 iscoupled to a diversion means such as an opening/closing gate 9 to openand close a passage for which the shot peening device 2 communicateswith the vertical feeder 6 through the chute 8. The gate 9 has a closedposition and an open position. By an aperture in the open position, thegate 9 can be variably regulated.

The lower end of the respective gate 9 is coupled to an inlet 10. Inturn it is coupled to the corresponding shot peening device 2 forintroducing the shot particles.

A removing means such as the respective separators 11 are arrangedbeneath the corresponding chute 8 such that a part of it is housed inthe cabinet 1 at a level lower than the corresponding gate 9. Namely,the separators 11 are located under the upper surfaces of the cabinet 1.

In this embodiment, when the gates 9 open to supply the shot particlesto the shot peening devices and thus to be projected therefrom, some ofthe shot particles from the respective gate 9 overflow in order tosupply shot to the corresponding separator. However, if the gate 9 is inthe closed position, then all the shot particles are supplied to theseparator 11.

Again in reference to FIG. 1, the interior of the cabinet 1 defines apeening chamber 12. In it the shot particles are projected to a workpiece to be supported on the movable carriage 3 and a carry-in-and-outpassage (not shown). The movable carriage 3 includes hangers 13 arrangedin the peening chamber and the carry-in-and-out passage, a revolvingplate (not shown, but it is arranged in the upper side in the interiorof the chamber 1) for rotatably suspending the hangers 13, and a motor14 for rotating the revolving plate around its central axis of rotation(not shown). The movable carriage 3 also includes a rotating plate (notshown) that is connected to the hangers 13 and is arranged above therevolving plate, and a conventional motor (not shown) for rotating therotating plate in the peening chamber 12.

The circulation unit R of the shot-blasting machine operates as follows.First, two of the impeller type shot peening devices 2 project the shotparticles on work pieces that are supported by the hanger-type movablecarriage 3 in the cabinet 1. The shot particles impact the work piecesand then fall under them because of their gravity. The fallen shotparticles are guided on the inclined surfaces of a pair of the grooves 5of the lower part of the cabinet 1 such that they are supplied to two ofthe cross feeders 4.

Because employing the compact cross feeders or the horizontal screwconveyers 4 in order to make the machine compact also reduces thetransportation capacities, so some means to prevent an overload of themis desirable. To this purpose, for example, a partition is arranged inthe central top of the W-shaped cross-section in the lower space in thecabinet 1. Because the fallen shot particles flow through the right anleft grooves equally, the overload of the cross feeders 4 can beprevented. Alternatively, a passage may be provided to lead the shotparticles that overflow from one groove to another groove. To preventthe overload of the cross feeders 4, it is preferable that the samequantity of the shot particles to be projected from the two shot peeningdevices 2 be the same.

Subsequently, the shot particles are cross-fed by two of the crossfeeders 4, and thus are gathered at two places outside the cabinet 1.These gathered shot particles are then upwardly fed by the verticalfeeders 6, and arrive at the gates 9 from the upper parts of verticalfeeders 6 and pass through the chutes 8. When the gates 9 open to supplythe shot particles to the shot-peening devices 2 for being projectedagain, some of the shot particles overflow from the gates 9 and aresupplied to the separator 11. Therefore, because not all of the shotparticles need to be supplied to the separator 11, it can be compact.

The blasting machine may be equipped with a classification device 15 in,e.g., the side of the cabinet 1 so as to classify the diameters of theshot particles. The shot particles that have been passed through theseparators 11 to separate the impurities are transferred to theclassification device 15 to further separate the impurities, and theyare fed back to the cross feeder 4.

Because two of the cross feeders 4 are used in parallel, the height ofone of them can be lower than that where just one large cross feeder isused. Furthermore, because the lower cross section of the cabinet 1includes the plural grooves and thus the plural inclined surfaces, thelower part of the cabinet 1 can be more compact than where just oneinclined surface is used to gather the shot particles to just onegroove. Thus the entire cabinet 1 can have a low profile.

If all the shot particles are always supplied to the separator, a tallseparator should be installed above the gates of the passages for theshot particles. Thus such a machine has a very great height. In thisembodiment, when the gates 9 open to supply the shot particles to theshot peening devices 2 to be projected again, some of the shot particlesoverflow the gates 9, to be supplied to the separator 11, as describedabove. Accordingly, no tall separator need be installed above the gatesof the passages for the shot particles. Therefore, the blasting machinecan have a low profile. In addition, because the separator 11 can belocated at a low position by the gates 9, the blasting machine can bemore compact. Furthermore, the blasting machine can be more compact,since the separator 11 can be housed in the cabinet 1.

In this embodiment, two of the separators 11 are arranged, but just oneseparator may be used. In this case, the shot particles that overflowthe gates 9, as described above, may pass through one separator, and maybe distributed to two shot preening devices 2.

Although two of the shot-peening devices 2 are mounted on the opposedsidewalls one-by-one in this embodiment, they can be mounted on theopposed sidewalls two-by two, or two of the shot-peening devices 2 canbe mounted on just one sidewall, above and below it.

Although impeller-type shot-peening devices are mounted on the topsurface of the cabinet in the forgoing Japanese Patent Early-PublicationNo. 11-239973, two of the impeller-type shot-peening devices 2 aremounted on the sidewalls of the cabinet 1 in this embodiment. Becausethe impeller-type shot-peening device 2 is larger than a nozzle typeshot-peening device for nozzle-jetting the shot particles withcompressed air, it is preferable that they be mounted on the sidewallsof the cabinet 1, rather than the top surface of it, to reduce theheight of the shot-blasting machine. However, the present invention isnot limited to a blasting machine using the impeller-type shot—preeningdevices 2, as illustrated. The present invention may constitute, forexample, an air-blasting machine device using nozzle-type shot-peeningdevices.

In the embodiment of the invention, the materials of the work piece tobe treated may include ferrous metals, nonferrous metals, plastic,ceramics, glass, and materials of various kinds. However, if theimpurities caused by the projection of the shot particles are excessiveand if they exceed the capacity of the separators (eliminating means),some application may not result in a desirable effect. Therefore, themachine of the present invention is particularly suitable for anapplication in which the impurities caused by the projection of the shotparticles to the work pieces are scarce, or an application for precisionwork pieces. For example, it is suitable for peening a forged product,for scaling a heat-treated product, and for removing a casting fin of acast product.

The Second Embodiment

FIG. 3 shows a cross section of the air-blasting machine of the secondembodiment of the present invention. This shot-blasting machine includesa cabinet (or a housing) 21, and two nozzle type shot-peening devices 22mounted on the opposed sidewalls of the cabinet 21, a table type,movable carriage 23 located within the cabinet 1 for transporting a workpiece W, and a circulation unit S for collecting shot particles that areprojected to the work piece and for recycling them to the shot peeningdevices 22.

Like the cabinet 1 of the first embodiment, a groove 25 having inclinedsurfaces is provided in the lower part of the cabinet 21 of the secondembodiment, to avoid having a pit for the installation of the machine.The second embodiment uses just one groove 25, although the firstembodiment uses two grooves 5. In the groove 25, a horizontal crossfeeder 24 is received such that the projected shot particles aregathered on one location on the outside of the cabinet 21. The crossfeeder 24 is a horizontal screw conveyor, the same as the cross feeder 4of the first embodiment. The traveling direction of the cross feeder 24or the longitudinal direction of the groove is the normal directionagainst the surface, as in FIG. 3. The bottom end of the groovereceiving the cross feeder 24 does not protrude from the bottom end ofthe cabinet 21. The bottom ends of the cabinet 21 and the cross feeder24 (and the proximal end of a vertical feeder 28 as described below)will be located above the level of a floor (or a base) on which themachine is to be installed. Therefore, the machine needs no pit for itsinstallation.

The movable carriage 23 includes a rotating table 26, and a driven table27, which is located on the rotating table 26 such that they will berotated in unison. The work piece W is loaded on the driven table 27, asillustrated by dashed lines in FIG. 3.

As shown in FIG. 4, the shot circulation unit or system S includes theforgoing cross feeder 24, the vertical feeder or vertical screw conveyor28 for upwardly feeding the shot particles that are gathered on onelocation outside the cabinet 21 by the cross feeder 24, and oneseparator 33 (see FIG. 5), which communicates with the vertical feeder28 such that it isolates impurities from the shot particles to besupplied to the shot-peening device 22. The proximal end of the verticalfeeder 28 is located above the bottom end of the cabinet 21, like thevertical feeder 6 of the first embodiment.

The second embodiment is equipped with one cross feeder 24, one verticalfeeder 28, and one separator 33, although the first embodiment isequipped with two cross feeders 4, two vertical feeders 6, and twoseparators 11.

A motor M is drivingly connected to one side of the upper portion of thevertical feeder or vertical screw conveyor 28. The other side of theupper portion of the vertical feeder 28 communicates with a chute 30.The lower end of the chute 30 is connected to a gate 31 to open andclose a passage by which the shot-peening device 22 communicates withthe screw conveyor 28 through the chute 30. The gate 31 is the same asthe gate 9 in which a divergence in the open position is variablyadjusted. The lower end of the gate 31 is connected to an inlet 32 whichin turn is connected to the two shot peening devices 22 for introducingthe shot particles via a distributor 34.

As shown in FIG. 5, the separator 33 is arranged such that itcommunicates with the lower side of the chute 30, and a part of it ishoused in the cabinet 21 at a level lower than the gate 31. Namely, theseparator 33 is located under the upper surfaces of the cabinet 21.

In this embodiment, like the first embodiment, when the gate 31 opens tosupply the shot particles to the shot peening devices 22 and thus toproject them to the work piece therefrom, some of the shot particlesfrom the gate 31 overflow in order to supply the overflow of theparticles to the separator 33 via the chute 30. Therefore, because allthe shot particles need not be supplied in the separator 33, it can becompact, like in the first embodiment.

The shot circulation unit or system S of the air-blasting machine ofthis embodiment operates as follows. First, two of the nozzle type shotpeening devices 22 project the shot particles on a work piece on thedriven table 27 of the movable carriage 23 in the cabinet 21. The shotparticles impact the work pieces and then fall under it due to theirgravity. The fallen shot particles are guided on the inclined surfacesof the groove 25 of the lower part of the cabinet 21 such that they aresupplied to one cross feeder in the groove 25. Subsequently, the shotparticles are cross-fed by the cross feeder 24, and thus are gathered atone place, outside of the cabinet 21. These gathered shot particles arethen upwardly fed by the vertical feeder 28 that is located laterally ofthe cabinet 21, and supplied to the nozzle type shot peening devices 22and the separator 33, via the gate 31 and the chute 30.

The shot particles that have been passed through the separator 33 toseparate the impurities are fed back to the cross feeder 24.

In this embodiment, as described above, because the separator 33 of thecirculation unit S is located beneath the top surface of the cabinet 21,the entire blasting machine can be compact.

The shot-peening devices 22 are not limited to the nozzle types. Thepresent invention may constitute, for example, a shot-blasting machineusing the inpeller-type shot-peening devices as described in the firstembodiment.

The Third Embodiment

FIG. 6 shows a cross section of the shot-blasting machine of the thirdembodiment of this invention. This shot-blasting machine includes acabinet 41, one impeller type shot-peening device 42 mounted on onesidewall of the cabinet 41, a drum type, movable carriage 43 locatedwithin the cabinet 41 for supporting and transporting a work piece orwok pieces, and a circulation unit T for collecting shot particles thatare projected to the work piece and for recycling them to theshot-peening device 42. The shot-peening device 42 is not limited to theimpeller type. The present invention may constitute, for example, anair-blasting machine using one nozzle-type shot-peening device 22, asillustrated in the second embodiment.

Similar to the cabinet 21 of the second embodiment, a grove 45 havinginclined surfaces is provided in the lower part of the cabinet 41 ofthis embodiment. Thus a pit for the installation of the machine is notnecessary. In this grove, one horizontal cross feeder 44 is receivedsuch that the projected shot particles are gathered at one locationoutside of the cabinet 41.

The cross feeder 44 is a horizontal screw conveyor, the same as thefirst and second embodiments. Similar to the first and secondembodiments, the bottom ends of the cabinet 41 and the cross feeder 44(and the proximal end of a vertical feeder 47 as described below) willbe located above the level of the floor (or a base) on which the machineis to be installed. Therefore, the machine needs no pit for itsinstallation.

The movable carriage 43 includes a rotating drum 46, for transportingthe work piece to a location where it will be processed by shot peeing.

As shown in FIG. 7, the shot circulation unit T includes the foregoingcross feeder 44, one vertical feeder 47, which is located lateral to thecabinet 41, for upwardly feeding the shot particles that are gathered atthe one location outside the cabinet 41 by the cross feeder 44, and oneseparator (not shown, but similar to the separator in the secondembodiment), which communicates with the vertical feeder 47 such that itisolates impurities from the shot particles to be supplied to theshot-peening device 42. The vertical feeder 47 of this embodiment is avertical screw conveyor whose proximal end is located above the bottomend of the cabinet 21, similar to the first and second embodiments.

A motor is drivingly connected to one side of the upper portion of thevertical feeder or vertical screw conveyor 47. The other side of theupper portion of the vertical feeder 47 communicates with a chute 49,whose lower end is connected to a gate 50 (similar to the gate 9 in thefirst embodiment) to open and close a passage for which the shot-peeningdevice 42 communicates with the screw conveyor 47 through the chute 49.The aperture of the open position of the gate 50 is variably adjusted.The lower end of the gate 50 is connected to an inlet 51. In turn it isconnected to the shot-peening device 42 for introducing the shotparticles. The foregoing separator (not shown) is arranged such that itcommunicates with the lower side of the chute 49.

In this embodiment, similar to the second embodiment, when the gate 50opens to supply the shot particles to the shot peening device 42 andthus to project them to the work piece therefrom some of the shotparticles from the gate 50 overflow in order to supply the overflownparticles to the separator via the chute 49. Therefore, because not allthe shot particles need be supplied to the separator, it can be madecompact similar to the second embodiment.

The shot-blasting machine of this embodiment also includes a dustcollector 52. The dust collector 52 is integrally provided with thecabinet 41 such that it is fluidly connected to the interior of thecabinet 41. The dust collector 52 collects the dust in its lower part,in the environment where the air flows from the top down. To reduce thespace necessary for installation it is desirable that the dust collector52 be integrally provided with the shot-blasting machine. If the dustcollector is spaced apart from the shot-blasting machine, the ductbetween them tends to stay open longer, and thus a wider space is neededfor installation.

The circulation unit T of the blasting machine of this embodimentoperates as follows. First, one impeller type shot peening device 42projects the shot particles on a work piece or work pieces, which is orare supported by the movable carriage 43 in the cabinet 41. The shotparticles impact the work piece(s) and then fall beneath it by gravity.The fallen shot particles are guided on the inclined surfaces of thegroove 45 of the lower part of the cabinet 41 such that they aresupplied to one cross feeder 44 in the groove 45. Subsequently, the shotparticles are cross-fed by the cross feeder 44, and thus are gathered toone place outside of the cabinet 41. These gathered shot particles arethen upwardly fed by the vertical feeder 47, and supplied to theimpeller type shot peening device 42 and the separator, via the gate 50and the chute 49.

The shot particles that have passed through the separator to separateimpurities are fed back to the cross feeder 44. The dust collector 52collects the dust, for example, produced from the collisions between theshot-particles and the work piece, in the cabinet 41.

The Fourth Embodiment

FIGS. 8 to 14 show the shot-blasting machine of the fourth embodiment ofthe present invention.

The upper and lower portions of a box cabinet 61, which has acarry-in-and-out opening 61 a for a work piece or pieces W, are providedwith revolving plates 62. The upper revolving plate 62 and the lowerrevolving plate 62 are connected to each other by a plurality ofpartitions 63 (FIG. 11). The upper and the lower revolving plates 62 arerotated around their revolving axes 64 by a common first motor 65 (FIG.11).

The interior of the cabinet 61 is compartmented by the partitions 63such that it defines a projection chamber 66, in which the peening ofthe work piece(s) W is done and a carry-in-and-out chamber 67 (FIG. 11)for the work piece(s) W.

One example of the movable carriage of this embodiment is, but is notlimited to, a hanging holder, as illustrated. Hangers 68 (FIG. 8) arearranged in the projection chamber 66 and the carry-in-and-out chamber67. The hangers 68 are rotatably suspended from the upper revolvingplate 2 and are connected to a rotating plate 69 (FIG. 8) above therevolving plate 2. The rotating plate 69 is rotated by a second motor 70(FIG. 11) in the project chamber 66.

As shown in FIG. 9, a cross feeder or horizontal screw conveyer 71 forfeeding the projected shot particles in a horizontal direction isreceived in a groove 61A having inclined surfaces in the lower part ofthe cabinet 61.

The leading end of the screw conveyor 71 is connected to the proximalend of a bucket elevator 72 for upwardly feeding the shot particles thatare conveyed by the screw conveyor 71. This embodiment incorporates thebucket elevator 72 as a vertical feeder, although the first, second, andthird embodiments incorporate the vertical screw conveyor. However, theshot-blasting machine of this embodiment can be compact, since it isconnected to an outer sidewall of the cabinet 61, similar to thevertical screw conveyor of the first, second, and third embodiments.

The bottom end of the groove 61A, and thus the bottom surface of thecross feeder 71, is located slightly above the bottom end of the cabinet61. The proximal end of the vertical feeder 72 is also located above thebottom end of the cabinet 61 (see FIGS. 8, 9, and 10). Accordingly, themachine needs no pit for installation.

As shown in FIG. 11, shot-peening devices 73 for projecting the shotparticles that are conveyed by the bucket elevator 72 to the workpiece(s) are mounted on the rear surface 61 (the side of the projectionchamber 66) of the cabinet 61. The rear surface 61 is opposed to thefront surface 61 b having the opening 61 a (the side where a standingoperator O is illustrated). Although the shot-peening devices areillustrated as being impeller types, they may be replaced with nozzletypes.

The bucket elevator 72 is connected to one side 61 d that isperpendicular to the front surface 1 b and the rear surface 61 c of thecabinet 61. A dust collector 74 is connected to one side 61 e that isopposed to the side 61 d of the cabinet 61. In this embodiment, the dustcollector 74 is integrally provided with the shot-blasting machine toreduce the space for installation.

As shown in FIG. 10, the upper part of the bucket elevator 72communicates with a chute 75. The lower end of the chute 75 is connectedto a gate 76 to open and close a passage by which the shot peeningdevices 73 communicate with the bucket elevator 72 through the chute 75.The gate 76 has its closed position and open position, and a divergencein the opened position is variably adjusted. The lower end of the gate76 is coupled to an inlet 77. In turn it is coupled to the respectiveshot-peening device 73 for introducing the shot particles.

As shown in FIG. 12, the chute 75 communicating with the gate 76 alsocommunicates with a separator 78. The separator is, but not limited to,a known wind selection type separator, and may be replaced with amagnetic ore separator.

The separator 78 is housed in the cabinet 61 at a level lower than thegate 76. Namely, the separator 78 is located beneath the upper surfacesof the cabinet 61.

In this embodiment, similar to the forgoing embodiments, when the gate76 is open to supply the shot particles to the shot-peening devices 73and thus to project them to the work piece(s) W, some of the shotparticles from the gate 76 overflow therefrom in order to supply theoverflown volume to the separator 78 via the chute 30. Accordingly, theheight of the shot-blasting machine can be lower than that of theconventional machine, and similar to the forgoing embodiments.

The upper outer sidewall of the dust collector 74 is connected to ablower 79 (FIGS. 9 and 11). A suction tube 80 is connected to one outerside, which is perpendicular to the outer side on which the blower 79 isconnected, of the dust collector 74 (FIG. 11). The suction tube 80 isconnected to a sedimentation chamber 81, and in turn it communicateswith the separator 78 via a suction inlet 82 (FIG. 8). The dustcollector 74 is connected to the chute 75 via a first divided duct 80 a,which is divided from the suction tube 80 (see FIGS. 8, 9, and 10).Because the chute 75, as described above, communicates with the interiorof the cabinet 61 via the bucket elevator 72 and the screw conveyor 71,the dust collector 74 can be sucked from the interior of the cabinet 61.A second divided duct 80 b is divided from the suction tube 80 and isconnected to a source 84 for supplying a retarding agent to retard theignition phenomenon via a flexible hose 83.

As shown in FIGS. 13 and 14, a plurality of cartridge filters 85, whichcan be detachably mounted on the dust collector 74, are arranged inlines. Preferably, each cartridge filter 85 is generally entirely flat.This causes the dust filter to be made compact, since if the respectivecartridge filter 85 is flat the filling efficiency of the cartridgefilters in the dust collector 74 can be increased and thus thefiltration area can be increased, as compared to a non-flat or thickcartridge filter. Such a flat-shaped cartridge filter 85 is hereinreferred to as “the flat cartridge filter.”

For air washing of the cartridge filters 85, a pulse-jet mechanism 86 tointermittently blow compressed air inside the respective filter 85 isarranged above the filters 85 in the dust collector 74.

The operation of the machine of the fourth embodiment will now beexplained. First, the work piece W is suspended from one hanger 68 inthe carrying-in-out chamber 67. The first motor 65 is then operated torotate the revolving plates 62 about the revolving axes 64 by 180degrees such that the work piece W moves in the projection chamber 61.The second motor 70 is then operated to rotate the rotating plate 69 ofthe projection chamber 66 such that the work piece W rotates in theprojection chamber 66. Subsequently the gate 76 opens and thus the shotparticles are projected on the rotating work piece W in the projectionchamber 66 by the operation of centrifugal shot-peening devices 73. Theprojection of the shot particles to one work piece W is continued over adesired time. During the projection period of this one work piece W, thefollowing work piece W to be processed is suspended from an empty hanger68 in the carrying-in-out chamber 7 such that a plurality of work piecescan be continually processed.

The fallen shot particles from the projection chamber 66 are collectedwith the screw conveyer 71 such that they are transported to the bucketelevator 72. The shot particles are transported upward with the bucketelevator 72, such that they are dropped in the chute 75 for circulating.The transport volume of the bucket elevator 72 is set to become largerthan the total projected quantity of the shot particles from thecentrifugal shot-peening device 73. This causes some of the shotparticles in the chute 75 to overflow the gate 76 when the shotparticles are supplied into the shot-peening devices 73 by opening thegate 76. The overflown shot particles are supplied to the separator 78.However, while the first motor 65 is operated and thus the revolvingplates are rotated, the gate 76 is in its closed position. Therefore,all the shot particles that are transported upward with the bucketelevator 72 and are dropped in the chute 75 in such a period aresupplied to the separator 78.

The shot particles supplied to the separator 78 fall toward thedirection designated by an arrow of FIG. 12 such that they are collectedwith the screw conveyer 71. At this time, the interior of the separator78 is absorbed with the dust collector 74 through an absorption mouth 82of the separator 78. This causes impurities to be carried on a currentof air such that they are absorbed by the dirt collector 74 to separatethem from the shot particles. These absorbed impurities flow into thesedimentation chamber 81 in which light materials, e.g., fines, of theirsame specific gravity, are absorbed with an absorption duct 80, andheavy materials, e.g., the shot particles that are reusable, of theirsame specific gravity, are returned to the screw conveyer 71.

After the projection of the shot particles for the work piece W iscarried out over the desired time, the gate 76 is closed and the secondmotor 70 is stopped. Subsequently the first motor 65 is operated torevolve the revolving plates 62 around their revolving axes 64 by 180degrees. Therefore, the work piece W that is finished with theprojection processing is moved to the carrying-in-out chamber 67 fromthe projection chamber 66 while the following work piece W to beprocessed is moved into the projection chamber 66 from thecarrying-in-out chamber 67.

The incoming work piece W to be processed in the projection chamber 66is projected while it is rotating, the same as the processing for thepreceding work piece W, as described above. During this projection, thework piece W that is in the carrying-in-out chamber 67 is carried outtherefrom, while a further work piece W to be processed is nextsuspended from an empty hanger 68 in the carrying-in-out chamber 67.

By the forgoing processes being repeated, many work pieces W aretreated.

During the operation of the shot-blasting machine, the operation of theblower 79 causes an absorption effect. Thus, the impurities areabsorbed. They are such as fines from the absorption duct 80 and thefirst divided duct 80 a. Gases, which include impurities, flow in thedirection designated by the arrow in FIG. 13 into the dust collector 74.The gases that flowed in the dust collector 74 then flow into theinsides of the plural flat cartridge filters 85 from their outsides. Atthis time, the gases coming into the insides of the filters 85 arepurified, since the impurities in the gas stick to the outer surfaces ofthe filters 85. The gases that flowed in the insides of the filters 85flow above from the upper openings (not shown) of the filters 85 asclean gases and are absorbed by the blower 79 to drain them to theoutside of the machine.

The respective flat cartridge filter 85 is preferably backwashed, ifdesired, since the quantity of the impurities that adhere to the outersurface of it is increased, as the air purification is repeated. Thebackwashing of the flat cartridge filter 85 refers to washing to stopthe blocking of impurities that have stuck to the outer surface of thefilter 85 by the dust collection. To this purpose, compressed air isintroduced into the inside of the filter 85 to be backwashed through itsopening to cause the compressed air to flow from the inside to theoutside of the filter 85. The adhering impurities on the outer surfaceare then exfoliated. In this embodiment, the pulse-jet mechanism 86,described above, is operated to blow the compressed air into the insidesof the filters from their upper openings such that the filters arebackwashed. This backwashing of the filters can be made intermittentlyduring the operation of the shot-blasting machine.

The source 84 to supply the ignition restraint materials will now beexplained. The source 84 contains a compressed-air sprayer (not shown).The source is also filled with calcium carbonate powder as ignitionrestraining materials. During the operation of the shot-blastingmachine, the compressed-air sprayer blows compressed air into theinterior of the source 84 every appointed time to stir up the calciumcarbonate powder. This calcium carbonate powder that is stirred up ispreferably sucked into the dust collector 74 through the flexible hose83, the second divided duct 80 b, and the absorption duct 80. Becausethe powdery dust density in the dust collector 74 can thus be weakened,any ignition of the powdery dust in the dust collector 74 may beprevented.

Although some of the embodiments of the present invention have beendescribed, those skilled in the art can understand that the presentinvention is not limited to them, but various changes or modificationscan be made without deviating from the sprit of the appended claims.

As examples of the movable carriage to support a work piece, theforgoing embodiment shows the hanger type (the first and the fourthembodiment), the table type (the second embodiment), and the drum type(the third embodiment), although those skilled in the art may optionallyreplace them. Alternatively, one may use, for example, a conveyer type.Depending on the form of the movable carriage or supporter, for example,it may be integrally provided with the cabinet, and it may be providedwith a continuous accessway between the inside and the outside of thecabinet.

In the second, the third, and the fourth embodiments, one groove and onecross feeder in the lower part of the cabinet are employed, but they arenot limited to such. Plural grooves and the corresponding plural crossfeeders can be used, similar to the first embodiment. In this case, itis desirable to provide some means to prevent overload of the pluralcross feeders, for example, the partitions in the first embodiment.

If the plural groves and the plural cross feeders are used, based on theshape of a work piece plural grooves that have different shapes andplural cross feeders that have different capacities may be used.However, it is preferable that the plural cross feeders have samecapacity may be used in order to make the machine compact.

Because the shot-separators 11, 33 and 78 are located beneath the uppersurface of the corresponding cabinet, each separator can be designedsuch make that it is completely received in the corresponding cabinet sothat it cannot be seen from the outside of the cabinet.

1. An apparatus for a shot-peening treatment comprising a housing havingupper and bottom ends and defining an interior therein, a movablecarriage for movably supporting an object to be treated within saidinterior, at least one shot projection means for projecting shotparticles to the object supported on said carriage, a shot circulationsystem having a collecting level at which said projected and fallen shotparticles are collected and returned to said shot projection means torecycle and use the collected shot particles for projection wherein saidcollecting level is located at a level that is the same as or above thatof said bottom end of said housing, said circulation system having atleast one cross feeder that is arranged horizontally at said collectinglevel, for cross feeding collected shot particles, and at least onevertical feeder for upwardly feeding the collected shot particles thatare cross fed by said cross feeder, a diversion means that communicateswith said vertical feeder at a fixed position above said collectinglevel and having a closed position and an open position, an aperture ofwhich is adjustable, said diversion means in the closed positiondiverting all the collected shot particles that arrive at said fixedposition by means of said vertical feeder, and in the open positiondiverting some of the shot particles, based on said adjustable aperture,of the collected shot particles that arrive at said fixed position bysaid vertical feeder, said diversion means returning the shot particlesthat have not been diverted to said shot projection means; and at leastone removing means provided between said diversion means and saidcollecting level and disposed below said diversion means such that saidshot particles that are diverted by said diversion means pass throughtherein for removing impurities from these shot particles, said removingmeans returning the shot particles therefrom to said cross feeder. 2.The apparatus of claim 1, wherein said fixed position in which saiddiversion means is provided is located beneath the upper end of saidhousing.
 3. The apparatus of claim 2, wherein said removing means islocated in said housing.
 4. The apparatus of claim 3, wherein said crossfeeder, said vertical feeder, said shot projecting means, said diversionmeans, and said removing means are all plural, and the shot particlesthat are not diverted are supplied to respective shot projection meansfrom a corresponding vertical feeder and diversion means in an openposition.
 5. The apparatus of claim 1, wherein said cross feeder is ascrew conveyor arranged horizontally.
 6. The apparatus of claim 1,wherein said vertical feeder is a screw conveyor that is arrangedsubstantially vertically.
 7. The apparatus of claim 1, wherein saidvertical feeder is a bucket conveyor.
 8. The apparatus of claim 1,wherein the shot particles that are diverted by said diversion means inthe open position based on its adjustable aperture overflow from saiddiversion means into said removing means.
 9. The apparatus of claim 1,wherein said housing is provided with at least one elongated groovealong a traveling direction of said cross feeder such that said at leastone cross feeder is received in said groove at said collection levelthat is located above the bottom end of said housing, wherein saidgroove includes an inclined surface for guiding the shot particles tosaid at least one cross feeder.
 10. The apparatus of claim 9, wherein aplurality of said grooves is provided so that each groove receives onecross feeder such that plural cross feeders are arranged parallel toeach other.
 11. The apparatus of claim 10, wherein said apparatusfurther includes means for distributing the shot particles to respectivegrooves.
 12. The apparatus of claim 1, wherein said shot projectingmeans includes an impeller type shot-peening device or a nozzle typeshot-peening device.
 13. The apparatus of claim 12, wherein saidapparatus is a shot-blasting machine, an air-blasting machine, or ashot-peening system.
 14. The apparatus of claim 12 or 13, wherein saidprojection means is attached to a sidewall of said housing.
 15. Theapparatus of claim 14, wherein two impeller type shot-peening devicesare arranged on said sidewall near an upper and lower portion of thehousing.
 16. The apparatus of claim 1, wherein said carriage is any of aconveyor, a hanger, a table, or a drum.
 17. The apparatus of claim 1,wherein a dust collector is mounted on an outer sidewall of said housingto suck the interior of the housing through a suction tube.
 18. Theapparatus of claim 17, wherein said suction tube is connected to asource for supplying an ignition suppressant to restrain any ignition ofthe dust within said dust collector.
 19. The apparatus of claim 17 or18, wherein a plurality of flat cartridge filters are arranged in saiddust collector.
 20. The apparatus of claim 1, including a classificationdevice between said removing means and said cross feeder to classify thesize of the shot particles being returned.